Creating apps with private networks

[andyjy]

I understand from this post in the Fly community forum that it's possible to create apps in their own private network by providing a network name string in the network parameter when creating an app. (Also supported via flyctl app create --network network-name).

Would this be something acceptable for inclusion within this terraform provider? Would it be helpful if I had a stab at a draft PR? (Not experienced with go but it appears it should be relatively straightforward to add the additional parameter.. 🤞)

Cheers!